There is increasing and conclusive evidence that viruses are the etiological agent of certain types of human cancer, including human T-cell leukemia, lymphoma and cervical cancer. There is additional evidence that viruses may be required for certain forms of hepatocellular carcinoma and B cell lymphoma. Cancers arising secondarily to immunosuppression by the AIDS retrovirus, HTLV 3, are reaching epidemic proportions. The last few years have seen an explosion of research and information in this area. The time of the proposed meeting is appropriate for a wide-ranging discussion of this problem. In addition to studies of the biology and molecular biology of these viruses, topics will include the epidemiology of human cancer viruses and discussions of methods for their identification and for design of vaccines against them. There will be discussion of selected animal models as well. Together these topics should provide a badly needed overview of viruses and human cancer and should promote interchange not only among scientists present but provide a valuable reference book for the scientific community at large.